diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index c3831f6..9eb7005 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -379,6 +379,12 @@
 
 			session->vmlinux_maps[MAP__FUNCTION]->start = self->mmap.start;
 			session->vmlinux_maps[MAP__FUNCTION]->end   = self->mmap.start + self->mmap.len;
+			/*
+			 * Be a bit paranoid here, some perf.data file came with
+			 * a zero sized synthesized MMAP event for the kernel.
+			 */
+			if (session->vmlinux_maps[MAP__FUNCTION]->end == 0)
+				session->vmlinux_maps[MAP__FUNCTION]->end = ~0UL;
 
 			perf_session__set_kallsyms_ref_reloc_sym(session, symbol_name,
 								 self->mmap.pgoff);